The invention relates to coupling devices in general, and more particularly to improvements in devices for sealingly and separably coupling a first tubular member to a second tubular member, for example, for sealingly and separably connecting one end of a flexible hose to a fluid-conveying and/or confining part of a radiator in a motor vehicle.
U.S. Pat. No. 3,588,149 discloses a vacuum or pressure coupling device wherein a first coupling element with several claws can engage a second coupling element only when the two coupling elements assume predetermined angular positions relative to each other (a similar coupling device is disclosed in U.S. Pat. No. 2,684,256). The reason is that the claws must be moved behind a substantially radially extending rear flank of a rib on the second coupling element, and this can take place only when the claws are free to move first through axially extending gaps or slots between arcuate sections of the rib. The front flank of the rib extends radially of the second coupling element so that it cannot initiate a spreading apart of the claws such as would be necessary in order to guide the claws toward engagement with the rear flank of the rib. Therefore, the patented coupling devices cannot be manipulated by robots in automatic assembly plants (e.g., in automobile assembling plants) because a robot could attach the two coupling elements to each other only when the claws of the second coupling element would register with the slots of the rib on the second coupling element.